Interesting Research

Scientists say nerves use sound, not electricity

Friday, March 9, 2007 | 7:13 PM ET

The common view that nerves transmit impulses through electricity is wrong and they really transmit sound, according to a team of Danish scientists.

The Copenhagen University researchers argue that biology and medical textbooks that say nerves relay electrical impulses from the brain to the rest of the body are incorrect.

“For us as physicists, this cannot be the explanation,” said Thomas Heimburg, an associate professor at the university’s Niels Bohr Institute. “The physical laws of thermodynamics tell us that electrical impulses must produce heat as they travel along the nerve, but experiments find that no such heat is produced.”

Heimburg, an expert in biophysics who received his PhD from the Max Planck Institute in Goettingen, Germany — where biologists and physicists often work together in a rare arrangement — developed the theory with Copenhagen University’s Andrew Jackson, an expert in theoretical physics.

According to the traditional explanation of molecular biology, an electrical pulse is sent from one end of the nerve to the other with the help of electrically charged salts that pass through ion channels and a membrane that sheathes the nerves. That membrane is made of lipids and proteins.

Heimburg and Jackson theorize that sound propagation is a much more likely explanation. Although sound waves usually weaken as they spread out, a medium with the right physical properties could create a special kind of sound pulse or “soliton” that can propagate without spreading or losing strength.

The physicists say because the nerve membrane is made of a material similar to olive oil that can change from liquid to solid through temperature variations, they can freeze and propagate the solitons.

The scientists, whose work is in the Biophysical Society’s Biophysical Journal, suggested that anesthetics change the melting point of the membrane and make it impossible for their theorized sound pulses to propagate.

SAN DIEGO—Being one of the true geniuses of the modern era, Albert Einstein recognized that a useful method for understanding the brain’s role in creativity was to study the brains of highly creative people. He also realized that there would be a great deal of interest in examining his own brain after his death, so he willed that his brain be removed before cremation. However, nearly all of the 240 blocks into which Einstein’s brain was dissected were lost and never analyzed.

Thirty years later, the Brodmann’s area 39 portion of Einstein’s brain was analyzed histologically by Marian C. Diamond, PhD, and colleagues. They reported that this area of Einstein’s brain contained a higher proportion of glial cells versus neurons, compared with the brains of control subjects. Assuming that the paucity of cortical neurons was not the result of aging (the control subjects were significantly younger than Einstein at the time of his death), how did the loss of neurons relate to Einstein’s creative genius?

When Einstein was about age 3, his parents brought him to a pediatrician because he was not yet talking. Researchers have learned that Einstein had developmental dyslexia. More than a century ago, it was found that lesions of the left angular gyrus—ie, Brodmann’s area 39—induce acquired alexia. Therefore, it is possible that people with developmental dyslexia may also have abnormalities in this region, Kenneth M. Heilman, MD, suggested in his lecture at the 17th Annual Meeting of the American Neuropsychiatric Association. In his view, however, the high ratio of glial cells to neurons that was reported by Diamond et al was less a sign of Einstein’s dyslexia than an indication of the high degree of what Dr. Heilman refers to as “connectivity.”

After viewing photographs taken of Einstein’s brain before its dissection in 1955, Witelson and colleagues noted that Einstein had an enlarged left inferior and—unlike most human beings—undivided parietal lobe, suggesting that this bigger and more highly connected supramodal cortex gave Einstein an advantage in doing mathematics and spatial computations. In 1985, Geschwind and Galaburda posited that delay in the development of the left hemisphere of the brain may allow the right hemisphere, which mediates spatial computations, to become highly specialized. It was Einstein’s view that his own creativity was heavily dependent on spatial reasoning. Thus, the abnormal development of his left hemisphere may have led to the right hemisphere becoming highly specialized for spatial computations, Dr. Heilman theorized.

“If you have something going on in one side of the brain, [could] that ‘disinhibit’ the other side of the brain [into] developing even greater ability?” Dr. Heilman asked. “Could Einstein’s dyslexia and lack of development of his left hemisphere have allowed his right hemisphere to grow and be well connected and to have excellent modules?… People who have tremendous creativity also have tremendous connectivity.”

FINDING THE THREAD THAT UNITES

According to Dr. Heilman, who is the James E. Rooks, Jr, Distinguished Professor of Neurology and Health Psychology at the University of Florida’s College of Medicine in Gainesville, connectivity is a key component of “creative innovation,” a concept that combines two of the four stages of creativity—incubation and illumination (the others are preparation and verification)—identified by Hermann Helmholtz in 1826.

In an article titled “Creative Innovation: Possible Brain Mechanisms” appearing in Neurocase in 2003, Dr. Heilman and his colleagues, Stephen E. Nadeau, MD, and David O. Beversdorf, MD, defined creative innovation as “the ability to understand and express novel orderly relationships.” A high level of general intelligence, domain-specific knowledge, and special skills are necessary for creative innovation, but even when they coincide, these three components are not sufficient for creative innovation. One further crucial component is the ability to develop alternative solutions—otherwise known as “divergent thinking”—yet, even the coexistence of specialized knowledge and divergent thinking is not enough to enable an individual to find the thread that unites the two.

“Finding this thread might require the binding of different forms of knowledge, stored in separate cortical modules that have not been previously associated,” the authors wrote. “Thus, creative innovation might require the coactivation and communication between regions of the brain that ordinarily are not strongly connected.”

Based on the findings of anatomic studies, it appears that creative individuals such as Einstein may have alterations of specific regions of the brain’s posterior neocortical region. At the same time, it has been observed that creative innovation frequently takes place during times of diminished arousal (eg, sleep) and that many well-known creative people have experienced depression, suggesting that alterations of such neurotransmitters as norepinephrine might play a critical role in creativity. In the view of Dr. Heilman and his coauthors, highly creative individuals “may be endowed with brains that are capable of storing extensive specialized knowledge in their temporoparietal cortex, be capable of frontal mediated divergent thinking, and have a special ability to modulate the frontal lobe-locus coeruleus (norepinephrine) system, such that during creative innovation cerebral levels of norepinephrine diminish, leading to the discovery of novel orderly relationships.”

In his lecture and in a follow-up interview with NeuroPsychiatry Reviews, Dr. Heilman focused on the importance of divergent thinking in creative innovation, how our understanding of its neurobiologic underpinnings has evolved over the past two centuries, and the clinical implications of depression and other brain disorders for future neuropharmacologic treatments.

“To be creative, people need to break away from what they have been taught to believe, and thus divergent thinking is a critical element of creativity,” he said. “Patients who have their frontal lobe[s] removed or injured cannot perform divergent thinking…. The major hypothesis of this talk is that creativity is dependent upon the ability to diverge and then form innovative solutions.

“The development of innovative solutions is dependent on the ability to coactivate anatomically distinct representational networks that store different forms of knowledge. This simultaneous distributed activation … may allow people to develop alternative innovative solutions, thereby finding the thread that unites.”

ENCOURAGING CREATIVITY BY FOSTERING INDEPENDENT THINKING

Dr. Heilman cited several items that are important for clinicians to know to get a handle on current research into creativity and the brain. Besides the importance of both divergent and “convergent” thinking, he observed that “many people who are very creative have a higher incidence of mood and addiction disorders [and that while] many neurologic disorders can reduce creativity … there are some that might enhance creativity.”

As an example of the latter, he cited the work of Miller and colleagues at the University of California, San Francisco, describing a series of patients with frontotemporal dementia who acquired new artistic abilities despite evidence of deterioration in the left anterior temporal lobe (see NeuroPsychiatry Reviews, June 2003, page 1). “These are people who had no history of artistic production,” Dr. Heilman said. “They actually became creative—perhaps because the deterioration on the left side ‘disinhibited’ their right side, and the right side got creative doing artistic things.”

Regarding mood and addiction disorders, Dr. Heilman explored the links among creativity and sleep, dreaming, rest and relaxation, and depression, and observed that one thread uniting them all is changes in neurotransmitter systems. Two components indispensable to divergent thinking appear to be disengagement and the ability to develop alternative solutions. To arrive at a creative solution to a persistently unsolvable problem, an individual must often change the method by which he or she has already attempted to solve the problem—in other words, think outside the box. Observations on problem solving have included William James’ view, expressed in 1890, that the ability to switch strategies is integral to divergent thinking and Charles Spearman’s suggestion in 1931 that creativity results from bringing together two or more ideas that previously have been isolated. One way to solve a persistent problem, then, would be to see it in a “new light” by combining different forms of knowledge and cognitive strategies mediated by the two hemispheres of the brain.

Dr. Heilman cited as examples a number of scientists who reported solving a difficult scientific problem while asleep or when falling asleep or awakening from sleep. He also pointed to the association between creativity and novelty seeking and the high rates of alcoholism, drug abuse, bipolar depression, and monodepression among such creative types as writers, composers, musicians, and fine artists. Based on what is known from existing evidence, such associations raise more questions than answers, according to Dr. Heilman. “For example, does treatment of depression and bipolar disorder influence creativity, and what are the effects of different treatments?” he asked.

PROMOTING CREATIVE THINKING

Can creativity in individuals be encouraged regardless of the makeup of their brain, or are we limited by such factors as the number of glial cells and amount of white matter? “I believe creativity can be ‘encouraged,’” Dr. Heilman responded. “We have known for decades that when young rodents are put in a stimulating environment, they have a much richer neural network than their sibs who were not raised in this environment. Thus, bringing up children in an enriched environment and making certain that they receive a good education is critical for their brain development.

“The frontal lobes appear to be the part of the cortex that is most important for creativity, in that they are critical for divergent thinking and might modulate the coactivation of diverse cognitive networks so important in innovation. The means by which family and friends might be able to encourage the development of the frontal lobes is to encourage independent and divergent thinking.”

Apart from such sociocultural interventions, Dr. Heilman believes that there is a limit to the extent to which neuropsychiatry and neuroscience can enhance creativity, particularly with regard to the development of new neuropharmacologic treatments. “It is possible that certain drugs taken by people might enhance creativity and others inhibit creativity,” he said, citing an editorial titled “Cosmetic Neurology,” written by one of his former fellows, Anjan Chatterjee. “But physicians have learned that ‘when it is not broke, do not attempt to fix it.’ In other words, if you alter a person’s homeostasis, there might be a price paid.”

Having Less Power Impairs the Mind and Ability to Get Ahead

Being put in a low-power role may impair a person’s basic cognitive functioning and thus, their ability to get ahead, according to new research in Psychological Science. In their article, Pamela Smith of Radboud University Nijmegen, and colleagues Nils B. Jostmann of VU University Amsterdam, Adam Galinsky of the Kellogg School of Management at Northwestern University, and Wilco W. van Dijk of VU University Amsterdam focus on executive functions. Executive functions help people maintain and pursue their goals in difficult, distracting situations. The researchers found that lacking power impaired people’s ability to keep track of ever-changing information, to parse out irrelevant information, and to successfully plan ahead to achieve their goals.

In one experiment they conducted, the participants completed a Stroop task to exercise executive functions. Participants who had earlier been primed with a low-power word task made more errors in the Stroop task than those who had been assigned to a high-power group. Smith and colleagues also found that these results were not due to low-power people being less motivated or putting in less effort. Instead, those lacking in power had difficulty maintaining a focus on their current goal.

In another experiment, participants were asked to move an arrangement of disks from a start position to a final position in as few moves as possible, a task known to researchers as the Tower-of-Hanoi task. This task tests the more complex ability of planning. In some trials there was a catch: participants had to move the first disk in a direction that was opposite to its final position. Those who had been primed with a low power writing task made more errors and required more moves on these trials, demonstrating poor planning.

Smith and colleagues believe their results have “direct implications for management and organizations.” In high-risk industries such as health care, a single employee error can have fatal consequences. Empowering these employees could reduce the likelihood of such errors. Additionally, their work illustrates how hierarchies perpetuate themselves. By randomly assigning individuals to high- and low-power conditions, they demonstrate that simply lacking power can automatically lead to performance that reinforces one’s low standing, sending the powerless towards a destiny of dispossession.